Combined rule and protractor.



A. W. SANDELIN. COMBINED BULB AND PROTRAOTQR. APPLIOATION'PILED JUNE 21,1909.

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Patented Jan. 10,1911.

ALFRED W. SANDELIN, OF MINNEAPOLIS, HIINNESOTA.

COMBINED RULE AND PROTRACTOR.

Application filed June 21, 1909.

T 0 (ZZZ whom it may concern:

Be it known that I, ALFRED V. SANDELIN, a citizen of the United States,residing at Minneapolis, in the county of Hennepin, State of Minnesota,have invented certain new and useful Improvements in Combined Rules andProtractors; and I do hereby declare the following to be a full, clear,and exact description of the invention, such as will enable othersskilled in the art to which it appertains to make and use the same.

This invention relates to measuring instruments and has specialreference to a form of folding rule provided with a novel species ofjoint so arranged as to indicate the angle of opening of the rule.

The invention still more specifically refers to a folding rule providedwith a protractor around the axis thereof together with an improved formof indicator therefor.

In the ordinary form of rule which has a protractor at the center jointmuch difficulty is experienced in obtaining true angles for the reasonthat no indicator other than the rule joint end is provided and in orderto get a true indication it is necessary that the protractor division bebrought truly into alinement therewith. Experiment shows that this isalmost impossible to accomplish and the principal object of the presentinvention is to provide a form of indicator which will not interferewith the general construction of a rule of this character but which, atthe same time, will be of such nature as to make it extremely easy toproperly set the rule for any angle.

Another difliculty that has been experienced in the usual form of rulearises from the fact that after the rule has been used for some time thejoint ends become more or less bruised with the consequence that thevalue of one of these ends as an index is eliminated so that theprotractor feature of the rule becomes useless.

Another object of the present invention is to obviate this diiticulty byproviding an index the edge of which is not subject to bruising and wearso that its value for the purpose remains constant.

Vith the above and other objects in view the invention consists ingeneral of a pair of members connected by a rule joint, one of saidmembers having its joint end provided with a protractor and the otherwith an improved and novel form of index.

The invention further consists in certain Specification of Letterslatent.

Patented Jan. 10, 1911.

Serial No. 503,505.

novel details of construction and combinations of parts hereinafterfully described, illustrated in the accompanying drawings, andspecifically set forth in the claim.

In the accompanying drawings, like characters of reference indicate likeparts in the several views, and :Figure 1 indicates a rule having thejoint constructed in accordance with this invention. Fig. 2 is an endview of the joint.

The numeral 10 indicates the center joints of a rule which in thepresent instance is indicated as an ordinary two foot rule. One of thesemembers 10 is provided with a joint end 11 having a projection in theform of of a circle and this projection is reduced in thickness from thethickness of the rule body as clearly shown in Fig. 2 at 12. The othermember 10 has a joint end 13 provided with a projection similar in formto the projection 12, but in this instance the projection comprises apair of spaced members 14:. The member 12 lies between the members 14:and a pivot pin 15 passes through the centers of these members thusconstituting what is commonly known as a rule joint. Upon the outer faceof one of these spaced members 14 are protractor divisions 16. Securedto the rule end 11 and in such manner that it projects over the dividedmember 1a is an index plate 17. This index plate has one edge soarranged as to be truly radial from the center of the joint and theinner edge of the plate lies at an acute angle to the first mentionededge so that a small sharp point is formed which acts as an index forthe protractor scale. By reason of this plate lying upon the member 14the point is at no time subject to wear or injury so that its value asan index is not subject to diminution. It is to be noted that by reasonof the peculiar position of the plate 17 it serves the double functionof a pointer or index and a protractor for the end edge of the scale sothat the corner of the member to which the pointer is attached does notreadily become worn. Furthermore, the point projects sufficiently farover the member 14E that any one of the division lines marked on thatmember may be readily adjusted by bringing it up until it is cut in twoby the radial edge of the index adjacent its point.

It will be noted from the foregoing that the objects sought to beaccomplished have been achieved and that there has thus been provided asimple and efiicient device of the kind described and for the purposespecified.

Having thus described the invention, What is claimed as new, is

The combination With a rule joint comprising pivoted members one ofwhich is provided with a face having protractor divisions thereon; of anindex comprising a relatively thin plate having one edge supported onthe face of the other member, said plate having the end edge flush withthe end of the member Whereon it is supported and radial to the centerof the rule joint, said end edge extending to the corner of thesupporting member and protecting the end of said supporting member, theinner edge of said plate lying at an acute angle to the first mentionededge whereby an in dex point is formed, said index point being arrangedto project over the protraetor divided face of the first member.

In testimony whereof, I afiiX my signature, in presence of twoWitnesses.

ALFRED W SANDELIN.

lVitnesses C. E. JOHNSON, JACOB BROWN.

